Difference between revisions of "2020 AIME II Problems/Problem 4"

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==Problem==
 
==Problem==
 
Triangles <math>\triangle ABC</math> and <math>\triangle A'B'C'</math> lie in the coordinate plane with vertices <math>A(0,0)</math>, <math>B(0,12)</math>, <math>C(16,0)</math>, <math>A'(24,18)</math>, <math>B'(36,18)</math>, <math>C'(24,2)</math>. A rotation of <math>m</math> degrees clockwise around the point <math>(x,y)</math> where <math>0<m<180</math>, will transform <math>\triangle ABC</math> to <math>\triangle A'B'C'</math>. Find <math>m+x+y</math>.
 
Triangles <math>\triangle ABC</math> and <math>\triangle A'B'C'</math> lie in the coordinate plane with vertices <math>A(0,0)</math>, <math>B(0,12)</math>, <math>C(16,0)</math>, <math>A'(24,18)</math>, <math>B'(36,18)</math>, <math>C'(24,2)</math>. A rotation of <math>m</math> degrees clockwise around the point <math>(x,y)</math> where <math>0<m<180</math>, will transform <math>\triangle ABC</math> to <math>\triangle A'B'C'</math>. Find <math>m+x+y</math>.
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==Solution==
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After sketching, it is clear a <math>90^{\circ}</math> rotation is done about <math>(x,y)</math>. Looking between <math>C</math> and <math>C'</math>, <math>x+y-16=2</math> and <math>x-y=24</math>. Solving gives <math>(x,y)\implies(21,-3)</math>. Thus <math>90+21-3=\boxed{108}</math>.
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~mn28407
  
 
==Video Solution==
 
==Video Solution==

Revision as of 03:14, 8 June 2020

Problem

Triangles $\triangle ABC$ and $\triangle A'B'C'$ lie in the coordinate plane with vertices $A(0,0)$, $B(0,12)$, $C(16,0)$, $A'(24,18)$, $B'(36,18)$, $C'(24,2)$. A rotation of $m$ degrees clockwise around the point $(x,y)$ where $0<m<180$, will transform $\triangle ABC$ to $\triangle A'B'C'$. Find $m+x+y$.

Solution

After sketching, it is clear a $90^{\circ}$ rotation is done about $(x,y)$. Looking between $C$ and $C'$, $x+y-16=2$ and $x-y=24$. Solving gives $(x,y)\implies(21,-3)$. Thus $90+21-3=\boxed{108}$. ~mn28407

Video Solution

https://youtu.be/atqPgGG0Ekk

~IceMatrix

See Also=

2020 AIME II (ProblemsAnswer KeyResources)
Preceded by
Problem 3
Followed by
Problem 5
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All AIME Problems and Solutions

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